E36 M42 and E30 M42... possibilities?

[Jaredmac11]

I have a whole E36 motor and an early E30 M42 in parts so the possibilities are limitless.

The plan was to get this all in my e21, and as Im rounding the corner to the finish line, Im seeing that my plan to use the E36 late intake just isnt worth it.  Its too tall and too large, and the more I read the more I am seeing that the late E36, disa style, intake is more tuned to low-end torque but takes it from the top end (I could be wrong).

That being said, I would like to find a way to maintain the E36 knock sensors.  Is that possible?  I dont have a particular use for the sensors today since this engine is going to be stock NA, minus a performance chip tune.  My thought was the sensors would help the engine run better with the ECU but I really dont have an idea otherwise.

I wonder also if I could just take the E30 intake and plug it up to the e36 everything else.  Just looking at everything side by side... I think I could make it work.  I just wonder if the ECU would know what to do with the E30 intake?

[DesktopDave]

I like the way this is heading, but I have no idea if it'll work.

I'd suspect that the DISA valve could be simulated with a resistor, although it probably doesn't matter much. I've heard those manifolds are frequently non-operational at this vintage anyhow.

Otherwise, the motors are pretty much identical, correct? I do believe there are a few other detail differences between Motronic M1.7 (E30) and M1.7.2 (E36) wiring harnesses and pinouts. The DISA, EWS and knock sensors immediately come to mind.

[Jaredmac11]

The goal would be to maintain as much of the E36 wiring and piping as possible, but delete the unnecessary bits along the way.  Looking at the E30 'The Mess under the Intake' mod, it looks like after removing most of the junk, the e30 and e36 are pretty similar.  I have not cracked out the wiring diagrams for each system and traced wires... yet.

First thing..
The E30 intake and E30 valve cover have to go together.  The position of that vent hose is relocated on the e36 M42.  That vent hose goes to the throttle body directly on the e30.  On the e36, it goes to an early CCV, which is bolted on to some type of thermal housing between the upper and lower intake.  On the E30, this goes right to the throttle body.  I feel like its not much of a step back (if at all?) to vent to the throttle body and esentially delete the ccv.

The throttle position sensor looks identical but I havent found it yet on the wiring diagram to confirm differences.


I'll look at the fuel rails tomorrow. Odds are I can the e36 fuel rail in the e30.  Or maybe they are interchangeable. 

Otherwise it *could* be plug and play.  This is all guesswork here on my part.  This could be a lot of fuss for not a lot of gains.  To be honest Im only doing this because I've already bought new rubber for the e36 and Im hard headed.  I like to imagine 1.7.2 is a highly refined system that will get the most oomph from the M42 compared to the 1.7.  Realistically I know thats not the case and I'll probably be better off just taking a few steps back and going to the e30 system.

It wont be a loss at the end of the day.  E36 M42 head has lighter valves and the e36 timing case is improved from the E30.

[Jaredmac11]

Ran a deeper dive on the fuel rails today.  Again, I am not a knowledgeable resource, I just have the luxury of having all the parts in front of me to compare.

At first glance, the E36 injectors are much larger than the e30 injectors..
https://imgur.com/MayX7Vo

The E36 intake, obviously, allows for these larger injectors
https://imgur.com/5BhkOCr

Fortunately the e30 and e36 fuel rail plugs are identical and I could swap them (assuming it would work when swapped)
https://imgur.com/M9M9M0p


The only fear I have is that this is *all* guesswork here.  I *have* to get a chip for the E36 ECU to delete the EWS-II system.  Part of me wants to at least try it and see if it can be done, part of me just wants to play it safe.

There's a few other hoses going around the e36 I have to work out.  The DISA, some hoses from the throttle body, etc.   I dont know where those go or went so it will take more research.

I also wonder if I could take the E30 lower manifold and see if they can match the injector ports to the e36??  Probably a crazy thought there.
I'd love to know if size matters on those injectors and the E36 M42 is an improved injector.

Edit2:  Just ran in to this site: http://users.erols.com/srweiss/tableifc.htm
It looks like the E36 injectors are inferior to the E30 injectors, which is honestly surprising.

BMW	Part No.	cc /min	Est. HP - 80%	Est. HP - 95%
e36	0-280-150-501	191.8	28.1	33.3
e30	0-280-150-714	213.9	31.3	37.2

[benz-tech]

I don't think the e36 injectors work in the e30 mani. Or you can break the plastic sleeve off but it's  been a few years since I looked at it. I've run 2years with the disa gone and nothing plugged in. It sets a code but not a check eng light. Personally, I'd run all e36 stuff but with an e30 manifold.

[Jaredmac11]

I dont know about removing the plastic sleeve but the face of the injector is a wider diameter, I was thinking more to boring out more of the injector port/passage on the e30 intake, but thats a fool's folly.

Pi is apparently the multiplier for your engine swap budget as well.

Unfortunately that's the one truth ive found in this whole project.